Roof shell having an acoustic insulation layer

ABSTRACT

A motor vehicle roof shell having a rigid composite component having an inner side facing a vehicle interior, and an acoustic insulation layer disposed on the inner side of the composite component. The panel-type rigid composite component has at least one tray-like recess on its inner side, said recess being filled with an open-pored foam material which forms the acoustic insulation layer and whose surface is flush with a surface of the composite component surrounding the recess. A motor vehicle roof shell motor vehicle having a panel-type rigid composite component having an inner side, which faces the vehicle interior, and an acoustic insulation layer disposed on the inner side of the composite component, wherein the acoustic insulation layer is formed by at least one rigid-foam or semi-rigid-foam plate which is bonded to the inner side of the composite component and compressed that its volume is reduced compared to preassembly state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/919,293, filed Mar. 13, 2018, now U.S. Pat. No. 10,699,687, whichclaims priority from German Patent Application Number DE 10 2017 105 679.3, filed Mar. 16, 2017, which are hereby incorporated herein byreference in their entirety for all purposes.

FIELD

The invention relates to a roof shell of a motor vehicle, the roof shellhaving the features of the preamble of claim 1.

BACKGROUND

A roof shell of this kind is known from practice and can be a fixed roofof a motor vehicle or a roof segment of a retractable hard top of aconvertible vehicle, the retractable hard top comprising multiple rigidroof segments. The roof shell can also be realized as what is known as acomposite module which comprises a panel-type rigid composite componentwhich is provided with an additional acoustic insulation layer at itsinner side. The composite component can be of a sandwich design andcomprise a core layer which is formed by a paper honeycomb or a foammaterial, for example, and which is provided with aglass-fiber/polyurethane mixture on both sides. Moreover, the compositecomponent can comprise an outer skin of the vehicle roof in question,the outer skin thus matching the design of the vehicle in question. Theacoustic insulation layer serves to acoustically insulate the vehicleinterior from the surroundings of the vehicle. However, acousticinsulation layers used so far present the problem that seams between theacoustic insulation layer and the composite component as well asirregularities on the inner side of the composite component may becomeapparent on the acoustic insulation layer at the inner side of the roofshell, in particular at a headliner fabric applied thereto as a lining.

SUMMARY

The object of the invention is to provide a roof shell of the kindmentioned above that has an optimized acoustic insulation layer.

According to the invention, this object is attained by the roof shellhaving the features of claim 1.

Thus, a roof shell of a motor vehicle is proposed that comprises apanel-type rigid composite component having an outer side and an innerside, which faces a vehicle interior. Moreover, the roof shell comprisesan acoustic insulation layer disposed on the inner side of the compositecomponent. The composite component has at least one tray-like recess onits inner side, said recess being filled with an open-pored foammaterial which forms the acoustic insulation layer and whose surface isflush with the surface of the composite component surrounding therecess.

With the roof shell designed according to the invention, the edges ofthe composite component thus remain free of the acoustic insulationlayer. The acoustic insulation layer thus does not reach the edges ofthe rigid composite component. This ensures that the inner side of theroof shell can be lined and the lining can have an edge fold at itsedges that wraps around the edges of the composite component.Additionally, it should be made sure that the open-pored foam materialthat fills the tray-like recess does not shrink during setting so thatthere will be no height difference or gap between the surface of thecomposite component surrounding the recess and the foam material fillingthe tray-like recess. This ensures that the inner side of the roof shellcan be lined properly.

In a preferred embodiment of the roof shell according to the invention,the open-pored foam material is a fine-pored flexible foam. Inparticular, the fine-pored flexible foam can be a polyurethane foamhaving a density between 50 kg/m³ and 80 kg/m³.

Preferably, the foam material is introduced into the tray-shaped recessaccording to a foaming process in a foaming mold. A foaming process ofthis kind can be performed in short process times, i.e. at a high cyclerate. Moreover, the mold-based process in the foaming mold allowsachieving high process stability, which, in turn, has a positive effecton the expenditures required for quality control.

In the foaming process in the foaming mold, an external release agentacting as a pore opener is preferably used. This has a favorable effecton the acoustic insulation properties of the foam material.

The bottom of the tray-like recess can present irregularities orprotrusions or can be rippled. This may be caused by functional elementsintegrated in the composite component. The foam material forming theacoustic insulation layer accommodates these irregularities, i.e.encloses them, while being smooth and even, i.e. free of protrusions orsteps, at its surface. In this way, the system is independent of anyinfluences that may be caused by changes in geometry of the compositecomponent.

The invention also relates to a roof shell of a motor vehicle thatcomprises a panel-type rigid composite component having an outer sideand an inner side, which faces the vehicle interior. An acousticinsulation layer disposed on the inner side of the composite componentis formed by at least one rigid-foam or semi-rigid-foam plate which isbonded to the inner side of the composite component and compressed insuch a manner that its volume is reduced as compared to a pre-assemblystate.

By being compressed in a suitable pressing tool, the rigid-foam orsemi-rigid-foam plate, which is bonded to the composite component acrossa large surface or to parts thereof, accommodates irregularities andsurface protrusions of the composite component auf, whereas the outerside, i.e. the side of the foam material facing away from the compositecomponent, is smooth and even, thus allowing it to be lined with aheadliner, which then forms a class A surface. Thus, no additionalheadliner element is required.

The roof shell designed according to the invention and comprising therigid-foam or semi-rigid-foam plate is produced by first producing thecomposite component in a corresponding molding tool. Subsequently, therigid-foam or semi-rigid-foam plate is pressed onto the compositecomponent. For bonding it to the composite component, an adhesivesystem, such as a spray adhesive or the like, can be used. Joining andcompression preferably take place in a press.

If required, a pressing tool including component holders can be used. Inparticular, one tool half of the tool holds the composite component in aform-fitting manner, thus ensuring a homogenous pressure distributionduring compression and avoiding damage to the composite component. Asecond tool half can be of such a geometric design that heightdifferences, recesses and seams are pressed into the rigid-foam orsemi-rigid-foam plate during compression. These deformations arepreserved after the pressing process in the rigid-foam plate orsemi-rigid-foam plate, which is reduced in volume. Accordingly, heightdifferences, recesses and seams of the composite component due toinserts, for example, are pressed into the rigid-foam or semi-rigid-foamplate. Thus, the appearance of the roof shell on the inner side is notcompromised by gaps, ripples or other defects in the compositecomponent.

As apparent from the explanations above, the acoustic insulation layerprovided by the rigid-foam or semi-rigid-foam plate is preferably bondedto the composite component through a mold-based pressing process. Thisprocess can take place at high process stability and thus with littleexpenditure in terms of quality control. The resulting component, whichis composed of the composite component and the compressed rigid-foam orsemi-rigid-foam plate, can be easily lined while offering properacoustic insulation.

Furthermore, the roof shell comprising the compressed rigid-foam orsemi-rigid-foam plate is characterized by low production costs becauseonly little investment is required for the pressing tool as compared tofoaming molds. Moreover, a rigid-foam or semi-rigid-foam plate exhibitshigh dimensional stability.

The rigid-foam or semi-rigid-foam plate advantageously consists of anopen-pored rigid foam, which enhances the acoustic insulatingproperties.

Preferably, the rigid-foam or semi-rigid-foam plate has a densitybetween 50 kg/m³ and 150 kg/m³ when in the compressed state.

A polyurethane-ester foam, a polyethylene foam or any other foammaterial suitable for the respective roof shell can be used as thematerial for the rigid-foam or semi-rigid-foam plate.

In a specific embodiment, the roof shell according to the inventionforms a roof shell of what is known as a retractable hard top (RHT) of aconvertible vehicle, the retractable hard top being composed of rigidroof shells. However, the roof shell can also be a panel bow of what isreferred to as panel-bow top, which comprises a foldable top coverfabric.

The invention also relates to a method for producing of a roof shell ofa motor vehicle. In this method, the following steps are performed:

-   -   producing a panel-type composite element in a molding tool;    -   placing the panel-type composite element in a pressing tool;    -   placing a rigid-foam or semi-rigid-foam plate in the pressing        tool;    -   compressing the rigid-foam or semi-rigid-foam plate with the        composite component so that the volume of the rigid-foam or        semi-rigid-foam plate is reduced and the latter forms an        acoustic insulation layer of the roof shell.

Other advantages and advantageous embodiments of the subject-matter ofthe invention are apparent from the description, the drawing and theclaims.

Exemplary embodiments of a roof shell according to the invention areillustrated in a schematically simplified manner in the drawing and areexplained in more detail in the following description.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 shows a perspective top view of a roof shell of a top of aconvertible vehicle;

FIG. 2 shows a section through the roof shell of FIG. 1 along line II-IIin FIG. 1;

FIG. 3a shows a second embodiment of a roof shell according to theinvention prior to the joining of a composite component and an acousticinsulation layer; and

FIG. 3b shows the roof shell of FIG. 3a in the finished state.

DETAILED DESCRIPTION

FIGS. 1 and 2 illustrate a roof shell 10 that is a rigid roof segment ofa multi-shell retractable hard top of a convertible vehicle. The roofshell 10 is connected to two links 12 and 14 on either side of avertical longitudinal center plane of the roof so as to be connected toa top linkage of the retractable hard top.

The roof shell 10 is a composite element that comprises a compositecomponent 16 as a base, which comprises a core made of a paper honeycombor foam. The core is provided with a polyurethane/glass-fiber mixture onthe top and on the bottom. On its outer side, i.e. on the side facingaway from the vehicle interior, the composite component 16 is providedwith a plastic film 18, which forms the outer skin of the roof shell 10.

On its inner side, which faces the vehicle interior, the compositecomponent 16 has a tray-like recess 20 that is surrounded by a surface22 of the composite component 16 in the manner of a frame. The tray-likerecess is filled with an open-pored foam material, which forms anacoustic insulation layer 24. The open-pored foam material of theacoustic insulation layer 24 is a fine-pored flexible polyurethane foamhaving a density of about 50 kg/m³ to 80 kg/m³ and is introduced intothe tray-like recess 20 in its form-locked state according to a foamingprocess in a foaming mold. As can be seen in FIG. 2, the acousticinsulation layer 24 has a top side, i.e. a side facing away from theplastic film 18, which is flush with the frame-like surface 22 of thecomposite component 16. This means that there is no height difference orgap at the seam between the acoustic insulation layer 24 and the surface22.

Furthermore, the roof shell 10 has a fabric lining 26 on its inner side,said fabric lining 26 covering both the acoustic insulation layer 24 andthe surface 22 of the composite component 16 and having an edge foldthat wraps around the edges of the composite component 16. Since thesurface of the acoustic insulation layer 24 and the surface 22 areflush, the seam between these two areas cannot become apparent on thefabric lining 26 that forms the inner visible surface of the roof shell10. In order to achieve ideal acoustics, the surface 22 is kept as smallas possible so that the surface of the acoustic insulation layer 24 isas large as possible.

FIGS. 3a and 3b show an alternative embodiment of a roof shell 10′ ofwhat is known as a retractable hard top of a convertible vehicle. Theroof shell 10′, too, has a composite component 16′ as a base, whichcomprises a core made of a paper honeycomb coated with apolyurethane/glass-fiber mixture on both sides. At its outer side, thecomposite component 16′ has a plastic film 18, which forms the outerskin of the roof shell 10′, which faces the surroundings of the vehicle.

At its inner side, the composite component 16 is provided with anacoustic insulation layer 28 which is made of a rigid polyurethane-esterfoam or of a semi-rigid polyethylene foam and to which the compositecomponent 16 is glued and additionally pressed, as can be seen in FIG.3b , in such a manner that its volume is reduced as compared to thepre-assembly state, which is illustrated in FIG. 3 a. The rigid foam orsemi-rigid foam of the acoustic insulation layer 28 is open-pored andhas a density between 50 kg/m³ and 150 kg/m³ when in the compressedstate, which is illustrated in FIG. 3 b.

For production, the composite component 16′ is placed in a mold half ofa pressing tool. The uncompressed acoustic insulation layer 28 is placedin the other mold half. Additionally, the exposed side facing theacoustic insulation layer 28 is provided with an adhesive, such as aspray adhesive. Then, the pressing tool is closed in the direction ofthe arrows P in FIG. 3a , the two tool halves thus being moved againsteach other and the acoustic insulation layer 28 being pressed againstthe inner side of the composite component 16′ and bonded thereto via theadhesive layer. The volume of the acoustic insulation layer 28 isreduced in the process, as can be seen by comparing FIGS. 3a and 3b ,which means that its in thickness decreases. Additionally, anyirregularities or differences 30 in thickness of the composite component16 are accommodated by the acoustic insulation layer 28 because they arepressed into the rigid-foam and semi-rigid-foam material. The side ofthe acoustic insulation layer 28 facing the vehicle interior remainssmooth.

In a final step, the component provided with the acoustic insulationlayer 28 is provided with a fabric lining 26 that wraps around the edgesof the acoustic insulation layer 28 with an edge fold.

REFERENCE SIGNS

-   10 roof shell-   12 link-   14 link-   16 composite component-   18 plastic film-   20 recess-   22 surface-   24 acoustic insulation layer-   26 fabric lining-   28 acoustic insulation layer

The invention claimed is:
 1. A method for producing a roof shell of amotor vehicle, comprising the following steps: producing a compositepanel component in a molding tool, wherein the composite panel componentcomprises a plastic film which forms an outer skin of the roof shell anda core made of a paper honeycomb having two opposed sides and apolyurethane/glass-fiber mixture coated on both sides of the paperhoneycomb; placing the composite panel component in a first mold half ofa pressing tool; placing a foam plate in a second mold half of thepressing tool, wherein the foam plate comprises a rigid foam material ora semi-rigid foam material; and compressing the foam plate with thecomposite panel component so that: a volume of the foam plate is reducedand the composite panel component forms an acoustic insulation layer ofthe roof shell, and any irregularities or differences in thickness ofthe composite panel component are pressed into the foam material of thefoam plate so that they are accommodated by the foam plate as they arepressed into the foam material of the foam plate, wherein a side of thefoam plate configured to face a vehicle interior is smooth aftercompression.
 2. The method according to claim 1, further comprising:providing the foam plate and/or the composite panel component with anadhesive prior to compression.
 3. The method according to claim 1,further comprising: lining the acoustic insulation layer with aheadliner fabric or flock.
 4. The method according to claim 1, furthercomprising: lining the acoustic insulation layer with a headlinerfabric, wherein lining includes wrapping the headliner fabric aroundedges of the acoustic insulation layer with an edge fold.